A new study says providing shelter for the homeless with severe addictions and mental illness throughout British Columbia could save taxpayers millions of dollars.

"Addiction is the most prevalent mental health problem in both the street homeless and at-risk populations, followed by concurrent disorders and, less frequently, mental illness alone," the Simon Fraser University report says.

The paper — titled Housing and Support for Adults with Severe Addictions and/or Mental Illnesses in British Columbia — says providing non-housing services for such people currently costs the public system more than $55,000 per year per person. It says providing adequate housing and supports could reduce this cost to $37,000 per year.

The team of researchers — from Burnaby-based SFU, the University of British Columbia and the University of Calgary — says the overall "cost avoidance" of such a plan is about $211 million per year.

"The costs of providing supported housing and other health services to this population … is lower than the cost incurred through the use of emergency departments, the corrections system and emergency shelters when they are homeless," the report says.

And, it notes, the problem is not just one found in the province's big cities. Results were similar in 28 smaller B.C. communities researchers visited.

Further, the report concludes, people who fall under the auspices of the study are not unreachable and difficult to serve, as has so long been believed. It says they can accept and benefit from mental health and substance use services and can remain in stable housing with the appropriate supports.

The report supports better integration between municipalities and inter-ministry service providers such as corrections, housing, health and employment.

Another challenge is the lack of housing. The report notes the drop in the number of rooming houses due to gentrification, combined with rent increases, has caused increased homelessness.

These developments have left people out in the cold since the 1980s, its says.

And, the report says, inadequate attention is paid to preventing homelessness among those who have both addictions and mental illnesses.

"Little funding has been directed to addressing underlying causes," it says. "Managers and service providers understandably focus on stop-gap solutions to immediate crises."

The report from SFU's Centre for Applied Research in Mental Health and Addiction was commissioned in 2006 by the Mental Health and Addictions Branch of the B.C. Ministry of Health.

The aim of the work was to determine numbers, associated costs and solutions for helping adults with addictions or mental illnesses in the province.

The report says 130,000 people in B.C. meet the criteria for having severe addictions and/or mental illness.

Of those, it says, 39,000 people are inadequately housed with almost 19,000 at risk of being homeless. Those figures are on top of the staggering 12,000 who are considered "absolutely homeless."

But, says the report, there are currently only 7,741 beds available in the province for those at risk.